Rate of Change of Serial β–Human Chorionic Gonadotropin Values as a Predictor of Ectopic Pregnancy in Patients With Indeterminate Transvaginal Ultrasound Findings

Diagnosis and treatment of ectopic pregnancy

“…An increase over 48 hours of at least 66% has been used as a cutoff point for viability. 20,26,27 Ectopic pregnancy may present with rising, falling or plateau β-hCG levels; thus, serial measurement is most useful to confirm fetal viability rather than to identify ectopic pregnancy. In a patient with a subnormal increase in β-hCG concentration, nonviability is assumed, and more invasive investigations can be used to clarify the nature of the abnormality (i.e., miscarriage v. ectopic pregnancy).…”

Negative Pregnancy Test—Can It Confidently Rule out an Ectopic?

“…Review of the published work indicates a consensus that, whatever the site of pregnancy, a falling serum beta-hCG concentration justifies expectant management [3]. In the present case the low and falling serum beta-hCG suggested that the pregnancy was unlikely to be an ectopic pregnancy [4].…”

Differential Diagnosis of Ectopic Pregnancy - Morbidity and Mortality

“…The lower limit of normal rise in beta-HCG (using a 99% confidence interval) is 53% in 2 days [4]. Patients with a beta-HCG level that falls more than 50% in 2 days are at low risk of having an ectopic pregnancy [5].As ruptured ectopic pregnancies have been reported at a wide range of beta-HCG levels, the beta-HCG level should not be a factor in determining whether or not transvaginal ultrasonography should be performed. (The prevalence of false-positive serum hCG results is low, with estimates ranging from 0.01-2%.…”